Patalakh Irina, Wandersee Alexandra, Schlüter Julian, Erdmann Michael, Hackstein Holger, Cunningham Sarah
Department of Transfusion Medicine and Hemostaseology, Friedrich-Alexander University Erlangen-Nuremberg, University Hospital Erlangen, Erlangen, Germany.
Department of Chemistry and Biochemistry of Enzymes, Palladin Institute of Biochemistry of the National Academy of Sciences of Ukraine, Kyiv, Ukraine.
Transfus Med Hemother. 2024 Aug 21;52(2):120-131. doi: 10.1159/000535926. eCollection 2025 Apr.
Immune checkpoint inhibitors (ICIs) have revolutionized classical treatment approaches of various cancer entities, but are also associated with a number of side effects. One of these may be life-threatening clotting disorders with the risk of thrombotic or hemorrhagic complications, the mechanisms of which are still poorly understood. In the present study, we analyzed the direct effects of pembrolizumab, nivolumab, and ipilimumab on platelet aggregation as well as plasma coagulation followed by fibrinolysis in an ex vivo model.
Microplate spectrometry was used to analyze aggregation, coagulation, and fibrinolysis in platelet-free (PFP) and platelet-rich (PRP) healthy donor plasma samples treated with pembrolizumab, nivolumab, ipilimumab, and appropriate isotype controls. Aggregation was induced by TRAP-6. Clotting of PFP and PRP followed by lysis was initiated with a tissue factor in a mixture of phosphatidylserine:phosphatidylcholine and the addition of t-PA. Among other parameters, the area under the curve (AUC) was used to compare the effect of ICIs on aggregation, coagulation, and fibrinolysis.
Upon direct contact with platelets, pembrolizumab stimulated platelet aggregation in PRP, while nivolumab and ipilimumab promoted disaggregation with corresponding changes in the AUC. Pembrolizumab and nivolumab, both PD-1 receptor inhibitors, had no effect on the plasma coagulation cascade. Ipilimumab, a CTLA-4 receptor inhibitor, significantly increased the rate of PRP clotting. When clotting was followed by lysis, all ICIs were found to prolong the growth of the PRP-derived fibrin clot and delay its elimination. This was manifested by an increase in AUC relative to control PRP.
This study characterizes the potential impact of pembrolizumab, nivolumab, and ipilimumab on hemostasis. Nivolumab and ipilimumab are able to reduce aggregation and increase the procoagulant properties of platelets, which can cause side effects associated with hemostatic imbalance leading to thrombosis or bleeding. The observed ICI-specific effects may contribute to our understanding of the mechanisms by which ICI affects platelets and suggest how, in a clinical setting, to reduce coagulation disorders during ICI treatment in the future.
免疫检查点抑制剂（ICIs）彻底改变了各种癌症实体的传统治疗方法，但也伴随着许多副作用。其中之一可能是危及生命的凝血障碍，存在血栓形成或出血并发症的风险，其机制仍知之甚少。在本研究中，我们在体外模型中分析了帕博利珠单抗、纳武利尤单抗和伊匹木单抗对血小板聚集以及随后纤维蛋白溶解的血浆凝血的直接影响。
使用微孔板光谱法分析用帕博利珠单抗、纳武利尤单抗、伊匹木单抗和适当的同型对照处理的无血小板（PFP）和富血小板（PRP）健康供体血浆样本中的聚集、凝血和纤维蛋白溶解。通过TRAP-6诱导聚集。在磷脂酰丝氨酸：磷脂酰胆碱混合物中加入组织因子并添加t-PA启动PFP和PRP的凝血，随后进行溶解。在其他参数中，曲线下面积（AUC）用于比较ICIs对聚集、凝血和纤维蛋白溶解的影响。
与血小板直接接触后，帕博利珠单抗刺激PRP中的血小板聚集，而纳武利尤单抗和伊匹木单抗促进解聚，AUC发生相应变化。帕博利珠单抗和纳武利尤单抗这两种PD-1受体抑制剂对血浆凝血级联反应无影响。CTLA-4受体抑制剂伊匹木单抗显著提高了PRP的凝血速率。当凝血后进行溶解时，发现所有ICIs都延长了PRP衍生纤维蛋白凝块的生长并延迟其清除。这表现为相对于对照PRP，AUC增加。
本研究描述了帕博利珠单抗、纳武利尤单抗和伊匹木单抗对止血的潜在影响。纳武利尤单抗和伊匹木单抗能够减少聚集并增加血小板的促凝特性，这可能导致与止血失衡相关的副作用，进而导致血栓形成或出血。观察到的ICI特异性效应可能有助于我们理解ICI影响血小板的机制，并为未来在临床环境中如何减少ICI治疗期间的凝血障碍提供建议。
